Interlayer vibrational modes in few-quintuple-layer<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Bi</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Te</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Bi</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Se</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>two-dimensional crystals: Raman spectroscopy an

Zhao, Yixin; Luo, Xin; Zhang, Jun; Wu, Junxiong; Bai, Xiaohui; Wang, Meixiao; Jia, Jin‐Feng; Peng, Hailin; Liu, Zhongfan; Quek, Su Ying; Xiong, Qihua

doi:10.1103/physrevb.90.245428

Cited by 101 publications

(70 citation statements)

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“…The decreasing of the Raman peaks as the increasing of Bi composition mainly originates from the increase of molar mass [37]. The Raman peaks of as-grown Bi 2 Te 3 and Sb 2 Te 3 nanoplatelets agree well with other reported samples [38,40]. The continuous composition dependence of the Raman modes in Bi x Sb 2À x Te 3 nanoplatelets is also consistent with Bi x Sb 2À x Te 3 crystals synthesized by the Bridgman technique [37], which indicates that uniform composition tuning of ternary Bi x Sb 2À x Te 3 nanoplatelets is realized by our modified solvothermal synthesis method.…”

Section: Results and Discussion Morphology And Structuresupporting

confidence: 85%

Controlled growth of bismuth antimony telluride Bi Sb2−Te3 nanoplatelets and their bulk thermoelectric nanocomposites

et al. 2015

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Section: Results and Discussion Morphology And Structuresupporting

confidence: 85%

Controlled growth of bismuth antimony telluride Bi Sb2−Te3 nanoplatelets and their bulk thermoelectric nanocomposites

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“…7b are consistent with experimental data in Ref. 44, and similar results can be found for ABC-stacked Bi 2 Te 3 as well. Obviously, the evolution of LF Raman spectra with thickness in ABC stacking is also generalized, independent of the specific 2D materials.…”

Section: Application Of the Model To Other 2d Materialssupporting

confidence: 92%

“…7,9,33 They can be categorized into two types: in-plane shear and out-of-plane breathing vibration modes. Due to their greater sensitivity to interlayer coupling, LF Raman modes can directly probe the interfacial coupling, and they have been found as more effective indicators of the layer thickness [34][35][36][37][38][39][40][41][42][43][44][45][46] and stacking 24,[47][48][49][50][51][52][53][54][55] for diverse 2D materials. LF Raman spectroscopy is a rapidly developing field of research and has accelerated due to recent development of volume Bragg gratings for ultra-narrow optical filters with bandwidth about 1 cm -1 , which allows efficient cut-off of the excitation laser light without employing expensive triple monochromators for LF Raman measurements.…”

Section: Introductionmentioning

confidence: 99%

Interlayer bond polarizability model for stacking-dependent low-frequency Raman scattering in layered materials

et al. 2017

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Two-dimensional (2D) layered materials have been extensively studied owing to their fascinating and technologically relevant properties. Their functionalities can be often tailored by the interlayer stacking pattern. Low-frequency (LF) Raman spectroscopy provides a quick, non-destructive and inexpensive optical technique for stacking characterization, since the intensities of LF interlayer vibrational modes are sensitive to the details of the stacking. A simple and generalized interlayer bond polarizability model is proposed here to explain and predict how the LF Raman intensities depend on complex stacking sequences for any thickness in a broad array of 2D materials, including graphene, MoS 2 , MoSe 2 , NbSe 2 , Bi 2 Se 3 , GaSe, h-BN, etc. Additionally, a general strategy is proposed to unify the stacking nomenclature for these 2D materials.Our model reveals the fundamental mechanism of LF Raman response to the stacking, and provides general rules for stacking identification.

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confidence: 99%

“…This model allows us to deduce the frequency of optical phonons that are silent in bulk crystals, namely the low-frequency interlayer breathing mode (LBM) with B 2g symmetry, and the mid-frequency in-plane (iX) and out-of-plane (oX) modes with E 2u and B 1u symmetry, respectively (see Table II). Finally, our work may motivate related studies of Davydov splitting, force constants and surface effects in other layered crystals, such as black phosphorus [48], bismuth selenide and bismuth telluride [49].Methods N -layer MoTe 2 crystals were prepared by mechanical exfoliation of commercially available bulk crystals (2D semiconductors) onto Si wafers covered with a 90-nm or 285-nm-thick SiO 2 epilayer. The number of layers was first estimated from optical contrast and atomic force microscopy measurements, and further characterized using a home-built micro-Raman setup.…”

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Unified Description of the Optical Phonon Modes in N-Layer MoTe₂

et al. 2015

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N -layer transition metal dichalcogenides provide a unique platform to investigate the evolution of the physical properties between the bulk (three dimensional) and monolayer (quasi two-dimensional) limits. Here, using high-resolution micro-Raman spectroscopy, we report a unified experimental description of the Γ-point optical phonons in N -layer 2H-molybdenum ditelluride (MoTe2). We observe a series of N -dependent low-frequency interlayer shear and breathing modes (below 40 cm −1 , denoted LSM and LBM) and well-defined Davydov splittings of the mid-frequency modes (in the range 100 − 200 cm −1 , denoted iX and oX), which solely involve displacements of the chalcogen atoms. In contrast, the high-frequency modes (in the range 200 − 300 cm −1 , denoted iMX and oMX), arising from displacements of both the metal and chalcogen atoms, exhibit considerably reduced splittings. The manifold of phonon modes associated with the in-plane and out-of-plane displacements are quantitatively described by a force constant model, including interactions up to the second nearest neighbor and surface effects as fitting parameters. The splittings for the iX and oX modes observed in N -layer crystals are directly correlated to the corresponding bulk Davydov splittings between the E2u/E1g and B1u/A1g modes, respectively, and provide a measurement of the frequencies of the bulk silent E2u and B1u optical phonon modes. Our analysis could readily be generalized to other layered crystals.Keywords: Two-dimensional materials, layered crystals, transition metal dichalcogenides, MoTe2, Raman spectroscopy, interlayer breathing and shear modes, force constants, Davydov splitting, surface effects.Introduction In the wake of graphene, a vast family of layered materials is attracting tremendous attention [1]. Now available in the form of N -layer crystals, the latter exhibit peculiar physical properties that complement the assets of graphene and offer exciting perspectives to design van der Waals heterostructures [1]. Semiconducting transition metal dichalcogenides (MX 2 , with M = Mo, W and X = S, Se, Te) are among the most actively investigated layered crystals [2]. Indeed, although bulk MX 2 exhibit indirect bandgaps, monolayer MX 2 are direct bandgap semiconductors [3,4] with remarkable spin, valley [5] and optoelectronic properties [6]. More Generally, N -layer MX 2 crystals provide an ideal platform to uncover the impact of symmetry breaking and interlayer interactions on the electronic, optical and vibrational properties, from the bulk (three-dimensional) to the monolayer (quasi two-dimensional) limit.In particular, in N -layer MX 2 , interlayer interactions result in a splitting of all the monolayer phonon modes [7][8][9][10][11][12][13][14][15][16] (see Table I). The latter effect is known as the Davydov splitting [17] and is closely related to the force constants that govern the vibrational properties of MX 2 [9]. The Davydov splitting has been previously studied in polyaromatic molecules [18], thin films [19], and bulk layered crystals, ...

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Interlayer vibrational modes in few-quintuple-layerBi2Te3andBi2Se3two-dimensional crystals: Raman spectroscopy an

Abstract: Interlayer vibrational modes in few-quintuple-layer Bi2Te3 and Bi2Se3 two-dimensional crystals : raman spectroscopy and first-principles studies

Cited by 101 publications

References 41 publications

Controlled growth of bismuth antimony telluride Bi Sb2−Te3 nanoplatelets and their bulk thermoelectric nanocomposites

Controlled growth of bismuth antimony telluride Bi Sb2−Te3 nanoplatelets and their bulk thermoelectric nanocomposites

Interlayer bond polarizability model for stacking-dependent low-frequency Raman scattering in layered materials

Unified Description of the Optical Phonon Modes in N-Layer MoTe₂

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Interlayer vibrational modes in few-quintuple-layerBi2Te3andBi2Se3two-dimensional crystals: Raman spectroscopy an

Abstract: Interlayer vibrational modes in few-quintuple-layer Bi2Te3 and Bi2Se3 two-dimensional crystals : raman spectroscopy and first-principles studies

Cited by 101 publications

References 41 publications

Controlled growth of bismuth antimony telluride Bi Sb2−Te3 nanoplatelets and their bulk thermoelectric nanocomposites

Controlled growth of bismuth antimony telluride Bi Sb2−Te3 nanoplatelets and their bulk thermoelectric nanocomposites

Interlayer bond polarizability model for stacking-dependent low-frequency Raman scattering in layered materials

Unified Description of the Optical Phonon Modes in N-Layer MoTe2

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Unified Description of the Optical Phonon Modes in N-Layer MoTe₂